import numpy as np
import pandas as pd
arr1=np.arange(1,10).reshape(3,3)
df1=pd.DataFrame(arr1, columns=['a','b','c'])
df1.insert(0,'key',['001','003','002'])
print('第一个原始数据df1:\n',df1)
arr2=np.arange(10,14).reshape(2,2)
df2=pd.DataFrame(arr2, columns=['a','e'])
df2.insert(0,'key',['001','004'])
print('第一个原始数据df2:\n',df2)
df3=pd.concat([df1,df2])
print('纵向外合并的数据df3:\n',df3)
df4=pd.concat([df1,df2],keys=['df1','df2'],sort=True)
print('纵向外合并，标记每个对象，并按列标签排序的数据df4:\n',df4)
df5=pd.concat([df1,df2],join='inner',ignore_index=True)
print('纵向外合并并重新设置连续行标签的数据：\n',df5)